MAPS (Microprogrammable Arithmetic Processor System)

The functions of the single chips are: MM5700CA (AU Arithmetic Unit) MM5701CA/B (RU Register Unit) MM5703CB/C (CROM Control ROM) MM5705CA (CROM Control ROM) MM5702CA (T&C Timing & Control) MM5704CB (KI Keyboard Intf)

Please note: the DTL-gates of the glue-logic. Most of the chips have date codes from end 1971 to begin 1972. The letter-suffixes CA..CC indicate probably mask programmed chip-select options, which are also used by the i4004. Thus there was no need for explicit CS-decoders.

In opposition to the i4004, which has a 6-times multiplexed 4-bit bus, the MM5700 ist bitserial like the Mostek-microprocessor in the hp35. The word cycle is 76 bits long. Using BCD-arithmetik, the MM5700 is able to do, this is enough for a 16-digit mantissa, sign and a 2-digit exponent.

Informations about MAPS (Nat-Semi, 1972).